Transition metal (TM) and nitrogen co-doped carbon (T M-N -C) materials have emerged as the promising single-atom catalyst (SAC) for the electrocatalytic CO₂ reduction reaction (CO₂RR), for which the coordination environment of the anchored single atom plays an important role. Inspired by this, the C₃N monolayers embedded with the TM single atoms at the CC double vacancy, denoted as M-CC (MTi, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au), have been evaluated for CO₂RR by using the first-principles calculation. We find that the M-CC SACs are of high stability and metallic conductivity, beneficial for the electron transport during the electrocatalytic process. More importantly, all M-CC have high selectivity toward CO₂RR versus the hydrogen evolution reaction. Especially, Cu-, Co-, Fe-, and Mn-CC have acceptable or ultra-low limiting potentials of −0.68, −0.48, −0.83, and −0.24 V to produce HCOOH, CH₂O, CH₃OH, and CH₄, respectively. The catalytic activities of M-CC are correlated with the adsorption strength of the key intermediates, further rationalized by the bonding/antibonding population analysis. Our work proposes a new material platform to realize TM-C-N SACs for efficiently electrocatalytic CO₂RR, which could provide useful insights into the design of such catalysts.

过渡金属（TM）和氮共掺杂的碳（T MN -C）材料已经成为电催化CO ₂还原反应（CO ₂ RR）的有前途的单原子催化剂（SAC ），在此条件下，其配位环境锚定的单个原子起着重要作用。受此启发，在C C双空位处嵌入TM单原子的C ₃ N单层称为M-CC（M Ti，V，Cr，Mn，Fe，Co，Ni，Cu，Mo，Ru，Rh ，Pd，Ag，Os，Ir，Pt和Au）的CO ₂进行了评估RR通过第一原理计算。我们发现M-CC SAC具有高稳定性和金属导电性，有利于电催化过程中的电子传输。更重要的是，与氢释放反应相比，所有M-CC对CO ₂ RR的选择性都很高。尤其是，Cu-，Co-，Fe-和Mn-CC具有-0.68，-0.48，-0.83和-0.24 V的可接受或超低极限电势，可产生HCOOH，CH ₂ O，CH ₃ OH和通道₄， 分别。M-CC的催化活性与关键中间体的吸附强度相关，通过键/反键族分析进一步合理化。我们的工作提出了一个新的材料平台，以实现用于高效电催化CO ₂ RR的TM-CN SAC ，这可以为此类催化剂的设计提供有用的见识。